The Taliban have said they pose no threat to the west, in a statement apparently intended to influence the debate over the future of the war in Afghanistan.

The announcement appeared on ­several websites used by the Taliban. It will be scrutinised by Barack Obama's national security advisers, who are reported to be pressing him to shift the focus of the war from the Taliban in Afghanistan to ­al-Qaida in Pakistan.

Some of the advisers, along with Joe Biden, the vice president, argue that the Taliban are not a direct threat to the US but al-Qaida's deepening intrusion into Pakistan threatens to turn it into a destabilising base for terrorist attacks.

The Taliban statement said they are fighting to expel foreign invaders from Afghanistan and establish an Islamic state. "We did not have any agenda to harm other countries, including Europe, nor do we have such agenda today," said the statement on a known Taliban website.

"Still, if you want to turn the country of the proud and pious Afghans into a colony, then know that we have an unwavering determination and have braced for a ­prolonged war." The ­statement also said that those dying or displaced in ­Afghanistan "were not involved in the (9/11) events of New York".

The statement may be a sign that senior Taliban figures are reassessing the movement's longstanding, though often tense, alliance with al-Qaida. In a recent exchange of emails with the Guardian, a Taliban spokesman avoided questions on the relationship between the Afghan insurgents and Osama bin Laden. He said they closely monitored opinion in western Europe and policy arguments in the US.

In Washington, Obama has been holding a series of high-level meetings as he decides whether to accept the recommendation of the Nato commander in Afghanistan, General Stanley McChrystal, to deploy up to 40,000 more troops to combat the Taliban. Yesterday, Obama also spoke to Gordon Brown on issues including Pakistan and Afghanistan, a White House spokesman said.

The UN security council last night voted to extend the mandate of Nato's 65,000 force in Afghanistan for a year, underlining its backing at a time when US commitment to the war is under review.

McChrystal argues that, without a swift and significant increase in US troops, the war against the Taliban may never be won. But most of Obama's national security advisers favour shifting the focus to hunting down al-Qaida in Pakistan, because it poses a greater threat to the US. They argue that the Taliban and Bin Laden's followers are not inextricably linked, a view which would be appear to be reinforced by the Taliban statement. If that position were accepted, it might even open the way to dealings with the Taliban which would be unthinkable with al-Qaida.

Hillary Clinton, the secretary of state, and Robert Gates, the defence secretary, have argued the two groups remain closely tied, and that if the Taliban were to retake power in Afghanistan they would again provide a safe haven to al-Qaida.

It is unclear whether the Taliban's statement represents a shift in position, an attempt to influence a continuing debate, or both.